This invention relates generally to a fluid control for a hydraulic motor, and more particularly to a fluid control that is useful as a redundant or backup control for an aircraft electro-hydraulic system.
In an aircraft electro-hydraulic system, an electrical signal originating at a command station is transmitted to an electro-hydraulic servo valve. The electro-hydraulic servo valve controls a primary valve that directs the flow of fluid to and from a fluid motor. The fluid motor, in turn, actuates a flight control surface such as a rudder or aileron of the aircraft. In the event of a failure in the electro-hydraulic system, a mechanically controlled backup valve directs the flow of fluid to and from the fluid motor to provide backup actuation of the flight control surface.
One such aircraft electro-hydraulic system is disclosed in U.S. Pat. No. 4,138,088, the entirety of which is incorporated herein by reference.